Sigma term and strangeness content of octet baryons

By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark-mass dependence of octet members, we use $SU(3)$ covariant baryon chiral perturbation theory to perform the extrapolation to the physical up and down quark masses. Our Nf=2+1 lattice ensembles include pion masses down to about 190 MeV in large volumes (M_πL4), and three values of the lattice spacing. Our main results are the nucleon sigma term σ_πN=39(4)(_-7⁺¹⁸) and the strangeness content yN=0.20(7)(_-17⁺¹³). Under the assumption of validity of covariant baryon χPT in our range of masses one finds yN=0.276(77)(_-62⁺⁹⁰).